Driving assist apparatuses have been put into practice for easing the driver's operational burden during parking of a vehicle or other occasions requiring a skillful driving operation. JP H11-334470A (Patent Document 1) has disclosed, as an example of such a driving assist apparatus, a parking assist apparatus for appropriately providing information useful when parking a vehicle. This parking assist apparatus obtains a predicted traveling trajectory of the vehicle based on a steering angle, and superimposes this predicted traveling trajectory on a background image. The predicted traveling trajectory is obtained based on a relative equation between a steering angle, a wheelbase of the vehicle, and a turning radius. The predicted traveling trajectory is subjected to coordinate transformation based on a mapping correspondence between a coordinate system (X, Y) of a road and a coordinate system (x, y) on a display of a monitor apparatus, and is superimposed on a background image (Patent Document 1: Paragraphs 27 to 29, FIGS. 8 to 12, etc.).